Synthesis and structural characterization of PhP[(C5Me4)(2)], a monodentate chiral phosphine derived from intramolecular C-C coupling of tetramethylcyclopentadienyl groups: An evaluation of steric and electronic properties
Jh. Shin et al., Synthesis and structural characterization of PhP[(C5Me4)(2)], a monodentate chiral phosphine derived from intramolecular C-C coupling of tetramethylcyclopentadienyl groups: An evaluation of steric and electronic properties, INORG CHEM, 40(22), 2001, pp. 5626-5635
The chiral monodentate phosphine PhP[(C5Me4)(2)] is readfly obtained by oxi
dation of the lithium complex Li-2[PhP(C5Me4)(2)] with I-2, which couples t
he two cyclopentadienyl groups to form a five-membered heterocyclic ring. T
he steric and electronic properties of PhP[(C5Me4)(2)] have been evaluated
by X-ray diffraction and IR spectroscopic studies on a variety of derivativ
es, including Ph[(C5Me4)(2)]PE (E = S, Se), Cp*MCl4{P[(C5Me4)(2)]-Ph} (M =
Mo, Ta), Ir{P[(C5Me4)(2)]Ph}(2)(CO)Cl, and CpFe(CO){PhP[(C5Me4)(2)]}Me. For
comparison purposes, derivatives of the related phospholane ligand PhP[Me2
C4H6] have also been investigated, including Ph[Me2C4H6]-PS, Ir{Ph[Me2C4H6]
}(2)(CO)Cl, Ir{Ph[Me2C4H6]}(2)(CO)Me, Ir{PPh[Me2C4H6]}(COD)(Cl), and Pd{P[M
e2C4H6]-Ph}[eta (2)-C6H4C(H)(Me)NMe2]Cl. The steric and electronic properti
es of PhP[(C5Me4)(2)] are determined to be intermediate between those of PP
h2Me and PPh3. Thus, the crystallographic cone angles increase in the seque
nce PPh2Me (134.5 degrees) < PhP[(C5Me4)(2)] (140.2 degrees) < PPh3 (148.2
degrees), while the electron donating abilities decrease in the sequence PP
h2Me > PhP[(C5Me4)(2)] > PPh3. Finally, PhP[(C5Me4)(2)] has a smaller cone
angle and is less electron donating than the structurally similar phosphine
, PhP[Me2C4H6].